328 VOYAGE OF H.M.S. CHALLENGER. 



tcrtius of the Petrels is altogether unrepresented in the Laridae. The character of 

 the caeca in the two groups is also quite different, and there are no special osteological 

 resemblances between the two groups so far as I can see, for the mere schizognathous 

 character of the palate is, we now know, not necessarily a mark of affinity. The 

 character of the young plumage, the condition of the young birds, and the number, 

 shape, and coloration of the eggs — points on which some stress may be laid in questions 

 of this kind — are totally dissimilar in the two groups, as indeed are the habits of the 

 adult birds themselves, though no doubt both are " web-footed " and more or less 

 pelagic in habit. Such resemblances, however, can hardly be seriously considered as 

 indicating any real affinities. 1 



" L'Herminier, A. Milne-Edwards, and Huxley have all, in describing various points 

 in the osteology of the Tubinares, pointed out similarities of various kinds between their 

 osseous structure and that of various forms of the Steganopodes, though they still kept 

 them close to the Laridae. Eyton, on the other hand, places the various Petrels he 

 describes in the family " Pelecanidae," the Gulls forming a separate family by themselves. 



" But no one will be prepared, I think, to dispute that the Steganopodes are allied to 

 the Herodiones, including under that name the Storks and Herons, with Scopus, only. 

 Thus, on osteological grounds alone, there is sufficient ground for placing the Tubinares 

 in the vicinity of the Steganopodes and Herodiones. And, in fact, neglecting the 

 desmognathous structure of the palate,— the taxonomic value of which per se is becoming 

 more and more dubious as our knowledge of the structure of birds increases, — there is 

 little in the characters assigned to the groups Pelargomorphae and Dysporomorphae by 

 . Professor Huxley (I.e., p. 461) that is not applicable to the general Petrel type. 



"The completely double great pectoral muscle is a characteristic only found, as 

 already observed, in the Ciconiidae, Cathartidae, the Steganopodes (except Phalacrocorax), 

 and the Tubinares, and in all these forms it is associated with short colic caeca of peculiar 

 shape (absent altogether in the Cathartidae, as in some of the Tubinares), more or less 

 completely webbed feet, tufted oil-gland (except in the Cathartidae), holorhinal nostrils, 

 a tendency of the palatine bones to unite behind the posterior nares, truncated mandible, 

 broad, strong, well-developed sternum, and strongly curved, well-developed clavicles. 

 These birds also agree together in being ' Altrices,' the young birds being quite helpless 

 after birth, and requiring to be fed for a long time by their parents — and in generally 

 laying eggs of a white, or nearly white, colour. 



" The group so constituted, of which the Ardeidae and Falconidae must also be considered 

 as aberrant members, — the first family being closely related to the Ciconiidae through 

 Scopus, whilst the Falconidae are probably, though much more remotely, connected with 



1 No views regarding the affinities of the Petrels other than that to the Laridee already discussed, and that to the 

 Ciconiiform birds, have, so far as I know, been seriously advanced by ornithological writers, Professor Garrod having 

 abandoned his early idea that the Tubinares were probably related remotely to the Anseres and their allies (cf. Proc. 

 Zool. Soc. Lond., p. 112, 1874 ; Collected Papers, pp. 220 and 521). 



